The cariogenic potential of Streptococcus mutans appears to lie in the ability to synthesize extracellular glucans that are involved in both coherent interactions among these organisms and in their adherence to the tooth surface. Mechanisms by which these processes occur and methods to inhibit them are being actively investigated. A large number of substances that influence glucan synthesis, which include salts, proteins, antiseptics, antibodies and hydrolytic enzymes, have been found to have pronounced effects on either glucan mediated adherence or coherence or both in in vitro washed cell experiments. The effects are being explored with cells from strains of each of the five different serotypes of S. mutans, according to Bratthall. Toward the elucidation of the mechanisms of plaque formation and inhibition, relevant in vitro experiments involving chemicals, biological products, non-adherent mutants, and interactions with other oral bacteria will be carried out in in vivo animal studies.